Only a limited number of French vessels have authority to work in the area to the north of the island.

Jersey fishermen alerted the authorities and satellite monitoring was used to confirm the vessel had been fishing there in July 2011.

The environment department said Mr Lecuyer was cooperative throughout and attended the island voluntarily for interview.

Mike Smith, leader of the environment department's marine resources section, said the prosecution was evidence of the partnership between the department and local fisherman.

He said: "At a registered tonnage of 62 tonnes, the Penn Kalet is a relatively large fishing vessel and we would like to thank the Jersey fisherman who brought her presence in this area to our attention."